The –MultiTenant parameter is only available for a few cmdlets in a multi-tenant deployment of Exchange Server 2010 SP1. Using –MultiTenant specifies the search or operation should be performed across the entire forest and not just the organization currently scoped.
I have found this parameter useful in combination with the Get-MoveRequest and Get-MailboxRestoreRequest cmdlets.
If I want to decommission a database I have to move all the mailboxes using New-MoveRequest. Below using Get-Mailbox with -Database I am able to retrieve all mailboxes hosted on the database across the entire forest, that is apart from arbitration mailboxes.
Get-Mailbox -Database DAG1DB1 | New-MoveRequest –Target Database DAG1DB2
To view the progress you normally run Get-MoveRequest or Get-Mailbox –Organization “Org_Name” but this will only show results scoped to the administrators or specified organization.
Using Get-MoveRequest –MultiTenant will show results for all move requests across the entire forest. This can be piped in to other cmdlets, for example to check when the moves are complete and remove them.
Get-MoveRequest –MultiTenant
Get-MoveRequest –MultiTenant | Remove-MoveRequest
This is much simpler than running Get-Mailbox –Organization 100s or even1000s of times.
Daniel Noakes